Microsoft has said that the underpinnings (APIs and logo requirements) of the User Account Control security feature in Windows Vista won't change in Windows 7, but the actual user experience will. Intended to prevent unauthorized software installations, UAC is one of the most controversial features in Vista, drawing wide criticism for its intrusiveness. As a result, Microsoft says new features in Windows 7 will allow developers to reduce the number of User Account Control prompts, thereby shortening application installation times.

Improved graphics: Though Windows Vista's Aero environment is designed to take advantage of the power available in modern graphics processors, Microsoft apparently believes that more remains to be done. Among other things, company blogs have devoted considerable ink to discussing how applications could be optimized to look better on high-DPI (dots-per-inch) displays.

Energy-efficient computing: A description for a session at this October's Microsoft Professional Developers Conference says that with Windows 7, software developers will find it easier to design applications that "do not negatively impact mobile PC battery life."

World support: Another PDC session blurb says Windows 7 will include new globalization support that will make it easier to change the languages and other location-related features of applications.

Server version: This won't be a major release. In fact, Microsoft has said that the server version of Windows 7 will be what was originally planned as Windows Server 2008 release 2 (the initial release, hailed as one of the most significant Windows Server upgrades in years, is less than a year old, having shipped last February).

Networking, Printing and Search

The names of the 25 engineering groups working on Windows 7 provide some other insights into where Microsoft will be tinkering. An entire group is devoted to wireless networking, for example. A documents and printing group is no doubt one of the company's efforts to build support for the XPS (XML Paper Specification) document-printing format introduced with Windows Vista. In addition, the presence of a group called 'Find and Organize' suggests that Microsoft has not yet finished working on Windows' search capabilities.